Is there a format specifier that always means char string with _tprintf?

问题

When you build an app on Windows using TCHAR support, %s in _tprintf() means char * string for Ansi builds and wchar_t * for Unicode builds while %S means the reverse.

But are there any format specifiers that always mean char * string no matter if it's an Ansi or Unicode build? Since even on Windows UTF-16 is not really used for files or networking it turns out to still be fairly often that you'll want to deal with byte-based strings regardless of the native character type you compile your app as.

回答1:

The h modifier forces both %s and %S to char*, and the l modifier forces both to wchar_t*, ie: %hs, %hS, %ls, and %lS.

回答2:

This might also solve your problem:

_TCHAR *message;
_tprintf(_T("\n>>>>>> %d") TEXT(" message is:%s\n"),4,message);

回答3:

You can easily write something like this:

#ifdef _UNICODE
#define PF_ASCIISTR    "%S"L
#define PF_UNICODESTR  "%s"L
#else
#define PF_ASCIISTR    "%s"
#define PF_UNICODESTR  "%S"
#endif

and then you use the PF_ASCIISTR or the PF_UNICODESTR macros in your format string, exploiting the C automatic string literals concatenation:

_tprintf(_T("There are %d ") PF_ASCIISTR _T(" over the table"), 10, "pens");

回答4:

I found, that '_vsntprintf_s' uses '%s' for type TCHAR and works for both, GCC and MSVC. So you could wrap it like:

int myprintf(const TCHAR* lpszFormat, va_list argptr) {
    int len = _vsctprintf(lpszFormat, argptr); // -1:err
    if (len<=0) {return len;}
    auto* pT = new TCHAR[2 + size_t(len)];
    _vsntprintf_s(pT, (2+len)*sizeof(TCHAR), 1+len, lpszFormat, argptr);
    int rv = printf("%ls", pT);
    delete[] pT;
    return rv;
}
int myprintf(const TCHAR* lpszFormat, ...) {
    va_list argptr;
    va_start(argptr, lpszFormat);
    int rv = myprintf(lpszFormat, argptr);
    va_end(argptr);
    return rv;
}



int main(int, char**) { return myprintf(_T("%s"), _T("Test")); }

来源：https://stackoverflow.com/questions/5669173/is-there-a-format-specifier-that-always-means-char-string-with-tprintf

标签

windows

printf

tchar

format-specifiers